The design stage is a crucial phase in the Software Development Life Cycle (SDLC) where the overall system architecture, components, and their relationships are defined. The primary goal of the design stage is to translate the requirements gathered during the requirements analysis phase into a blueprint that developers can follow during the implementation phase. It helps ensure that the final product meets user expectations and requirements while maintaining quality, performance, and scalability.
The design stage can be divided into two main categories: high-level design and low-level design.
High-Level Design (HLD): In high-level design, the system is broken down into modules or components, and the relationships between these modules are established. This process involves defining the overall system architecture, identifying main components, and outlining their interactions. HLD often includes the following elements:
System architecture: Determines the structure and organization of the system, including the hardware, software, and communication components.
Data flow diagrams: Illustrate how data moves through the system, highlighting the processes, data stores, and external entities.
Entity-Relationship (ER) diagrams: Depict the relationships between data entities, typically used in database design.
Low-Level Design (LLD): Low-level design focuses on defining the detailed design of each module or component identified during the high-level design. This stage involves creating detailed data structures, algorithms, and interfaces for each module. LLD often includes the following elements:
Pseudocode: Provides a high-level representation of the algorithms and logic to be implemented in each module.
Flowcharts: Visually represent the flow of control through the system, emphasizing the decisions, loops, and branching in the logic.
Interface design: Specifies the inputs, outputs, and communication protocols between different components or modules.
Data structure design: Determines the organization, storage, and retrieval of data within the system.
During the design stage, it is essential to consider factors such as maintainability, modularity, reusability, and security to create a robust, efficient, and scalable software solution. Once the design stage is complete, the project moves to the next phase of the SDLC, which is the implementation or coding phase.
1: Briefly explain the purpose of the design stage in the SDLC. (2 marks)
2: What is the difference between high-level design and low-level design in the design stage of the SDLC? (2 marks)
3: Name two types of design documents commonly created during the design stage of the SDLC. (2 marks)
4: Explain the importance of considering usability during the design stage of the SDLC. (2 marks)
5: Describe the role of design patterns in the design stage of the SDLC and provide an example of a design pattern. (4 marks)